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JEE Main 2022 (28 Jul, Shift 2) · Types of Flow, Reynolds Number & Continuity

Types of Flow, Reynolds Number & Continuity question from JEE Main 2022 (28 Jul, Shift 2)

Q13JEE Main 2022 · 28 JUL · SHIFT 2Medium

Types of Flow, Reynolds Number & Continuity

A pressure-pump has a horizontal tube of cross sectional area 10 cm210\text{ cm}^2 for the outflow of water at a speed of 20 m/s20\text{ m/s}. The force exerted on the vertical wall just in front of the tube which stops water horizontally flowing out of the tube, is:

[given: density of water =1000 kg/m3= 1000\text{ kg/m}^3]

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Answer: (d)

  1. Force = rate of change of momentum =dmdtv=(ρAv)v=ρAv2= \dfrac{dm}{dt}v = (\rho A v)v = \rho A v^2 (water stopped by the wall).
  2. F=1000×10×10−4×(20)2F = 1000 \times 10\times10^{-4} \times (20)^2
  3. F=400 NF = 400\text{ N}
  4. So the answer is (d) 400 N400\text{ N}.
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